Modular strand guide roller

ABSTRACT

The invention is based on the object of creating a strand guide roller being configured in a modular manner, which can be retrofitted to different stand casting widths without any substantial effort, and which has a cooling effect starting from the core regions of the roller extending up to the region near the surface thereof, thereby improving the life of the strand guide roller and achieving a comparatively cost-effective maintenance. The problem is solved according to the invention in that a first centrally disposed, axially extending flow channel ( 11  and a second centrally disposed, axially extending flow channel ( 12 ) are present in each roller module ( 2, 3, 4 ), that flow channels ( 15, 16 ) are disposed in the region near the surface of each roller module ( 2, 3, 4 ), and that connecting channels ( 17 ) connect the respective flow channels ( 15 ) to the first separate flow channel ( 11 ), and that connecting channels ( 18 ) connect the respective flow channels ( 16 ) to the separate second flow channel ( 12 ).

The invention concerns a modularly constructed strand guide roller forthe strand guide unit of a continuous casting plant in accordance withthe features of the preamble of claim 1, a strand guide roller inaccordance with the features of claim 13, and a method for operating itin accordance with claim 14.

A strand guide roller is known from EP 1 485 218 B1, which, however,proceeding from the objective of the invention, focuses on a rotaryleadthrough for a cooling water inlet and outlet of a support and/ortransport roller pivoted at least at the end with journals in bearingblocks, especially in a continuous casting plant. The outer region ofthe water-cooled support and/or transport roller has axial channels andchannels that run into or out of these axial channels and to a centraldistribution system. The central distribution system consists of acentral bore in the support and/or transport roller and of a tubularline arranged therein, which has a central supply channel for thecooling water and with the central bore forms an annular channel for theremoval of the cooling water.

The strand guide roller disclosed in the cited document consists of twoor more roller segments, each of which is supported at its end. Thistype of end bearing of the individual roller segments is expensive andentails considerable labor for the assembly and disassembly of thebearing units during maintenance of the strand guide unit.

Furthermore, as a result of this type of end bearing of the rollersegments, strand guide units cannot be changed over to other castingmachine widths without considerable labor.

WO 2007/121821 A1 discloses a strand guide roller of a strand guide unitthat consists of at least two roller sections, on which a strand cast bya continuous casting machine is guided, according to which a plugconnection is formed between the two roller segments, and only onebearing is provided, which is designed as an undivided single bearing.Aside from a number of advantages over the cited document, the solecooling medium flow channel, which runs centrally over essentially thewhole width of the strand guide roller, fails to develop a sufficientcooling effect for the strand guide roller. Especially the region of thestrand guide roller near the surface does not experience sufficientcooling to reduce the wear of the strand guide roller that results fromchemical and mechanical stress. Therefore, the centrally running flowchannel serves primarily to cool the inner rings of the bearing in thearea of the journal of the strand guide roller or the roller segments.

The internally cooled strand guide roller additionally disclosed by thedocuments WO 2004/094087 A1 and EP 1 646 463 B1 comprises a centralrotatable shaft and several roller shells that have integrated coolantchannels and are secured against rotation and supported on the shaft.Practical experience shows that these strand guide rollers with rollershells slipped onto them not only show unsatisfactory cooling of theroller barrels but also an enormously high proportion of sealingelements and thus do not represent a maintenance-friendly andoperationally reliable solution.

Therefore, the objective of the invention is to create a modularlyconstructed strand guide roller which can be changed over to differentcontinuous casting widths without any great effort and which has acooling effect that extends from the core region to the region near thesurface and thus improves the service life of the strand guide roller.

A further objective of the invention is to create a modularlyconstructed strand guide roller that allows comparatively low-costmaintenance. Yet another objective of the invention is to create astrand guide unit with strand guide rollers that are improved withrespect to increased service life and easier maintenance.

In accordance with the invention, the objective is achieved by thefeatures of claim 1 and the features of claims 13 and 14. According tothe features of claim 1, the modularly constructed strand guide rollerfor the strand guide unit of a continuous casting plant comprises

-   -   at least a first roller module and a second roller module, where        the two roller modules are disposed side by side in the axial        direction, and the first roller module has a centrally located        roller journal at its end face that faces the second roller        module,    -   a middle bearing, which is arranged between the first and second        roller modules for mounting and supporting the roller journal of        the first roller module, where the middle bearing is an        undivided single bearing,    -   a plug connection formed between the second roller module and        the roller journal for plug connection of the first and second        roller modules with each other, and    -   a flow channel that runs centrally in the roller modules for        conveying a coolant, such that, in accordance with the        invention, the centrally running flow channel consists of a        first separate flow channel and a second separate flow channel,        and such that    -   the first and second separate flow channels of each roller        module are connected by connecting channels with flow channels        formed in the region near the surface.

In a further refinement of the invention, the flow channels formed inthe region near the surface of each roller module are present in pairs.In this regard, in a first flow channel of the paired flow channels, thecoolant flows in the opposite direction from the coolant that flows inthe centrally running flow channels, and in a second flow channel of thepaired flow channels, the coolant flows in the same direction as thecoolant that flows in the centrally running flow channels. An opencoolant circulation is thus formed in each roller module. At one end ofthe paired flow channels, a chamber is formed, which serves to deflectthe coolant within the first roller module and the following rollermodule. The chambers are tightly sealed from the outside with a cover,so that no coolant can escape.

In addition, the first flow channel of each pair of flow channels isconnected by a corresponding first connecting channel with the firstcentrally running flow channel, and the second flow channel of each pairof flow channels is connected by a corresponding second connectingchannel with the second centrally running flow channel.

In this regard, the connection is produced, for one thing, in such a waythat the first connecting channel connects the supply-side outlet of thefirst centrally running flow channel with the discharge-side inlet ofthe respective flow channel of the paired flow channels, and, foranother, in such a way that the second connecting channel connects thesupply-side outlet of the second respective flow channel of the pairedflow channels with the discharge-side inlet of the second centrallyrunning flow channel.

As a result of this type of course of the flow channels within theroller module in accordance with the invention, not only are the coreregion and the region of the bearing cooled, as is already known fromthe prior art, but also the region near its surface.

In a further refinement of the invention, when the plug connectionbetween the first and second roller modules has been effected, thesecond centrally running flow channel of the first roller module and thefirst centrally running flow channel of the second roller module areconnected by a coupling sleeve, so that the coolant can flow from thesecond centrally running flow channel of the first roller module intothe first centrally running flow channel of the second roller module.

The second roller module and each additional roller module of the strandguide roller is, where the totality of the construction of the flowchannels and connecting channels is concerned, constructed identicallyto the first roller module. For example, in the case of a strand guideroller with a first and a second roller module, a first open coolantcirculation is joined with a second open coolant circulation to form acommon open coolant circulation, such that the first coolant circulationcan be connected to a coolant inlet, and the second coolant circulationcan be connected to a coolant outlet.

Advantageously, the modularly constructed strand guide roller makes itpossible for the first time to construct a strand guide roller fordifferent continuous casting widths, which is adequately cooled both inthe core region and in the region near the surface.

Due to the small axial extent of the bearing gaps between the individualroller modules, the advantageous result is obtained that only greatlyreduced or minimized bulging of the slab occurs in the regions notsupported by the strand guide rollers.

The design of the flow channels in accordance with the invention allowsoverall improved cooling of the strand guide roller with the result thatthe service life of the roller is increased and that the spectrum ofsteel grades that can be cast is expanded.

The provision of detachable covers for the peripheral flow channels orthe chambers has the advantage that these would now be accessible andcould be cleaned.

With a helical arrangement of the peripheral flow channels, they can bearranged and operated in groups, e.g., as a multiple thread. A firstgroup could then be used for the forward movement of the coolant and asecond group for its return movement.

A variable or alternating flow direction of the coolant in adjacentstrand guide rollers, adjacent roller segments, or in upper and lowerframes of a segment helps to even out the cooling effect on the strandor slab.

Further advantages and features of the present invention are apparentfrom the dependent claims and the description of a specific embodimentillustrated in the accompanying drawings.

FIG. 1 is a cross-sectional drawing, along sectional line A-A in FIG. 4,of a strand guide roller that consists of three roller modules.

FIG. 2 shows detail “Z” in FIG. 1 with an enlarged view of the flowchannels and connecting channels that convey the stream of coolant fromthe core region to the region near the surface.

FIG. 3 is a cross section of the strand guide roller in an enlarged viewalong line D-D in FIG. 1.

FIG. 4 is a cross section of the strand guide roller in an enlarged viewalong line B-B in FIG. 1.

FIG. 5 is a view of the second or middle roller module in direction “A”in FIG. 6.

FIG. 6 shows the second or middle roller module of the strand guideroller in the longitudinal section along line C-C in FIG. 5.

FIG. 7 is a side view of the second or middle roller module of thestrand guide roller according to FIG. 6.

The strand guide roller 1 shown in FIG. 1 consists of a first rollermodule 2, a second roller module 3, and a third roller module 4. All ofthe roller modules are assembled into a strand guide roller according tothe prior-art document WO 2007/121821, specifically, by a first plugconnection between the second or middle roller module 3 and the innerroller journal 2.1 of the first roller module 2 and by a second plugconnection between the third roller module 4 and the inner rollerjournal 3.1 of the second or middle roller module 3.

The inner roller journal 2.1 of the first roller module 2 is mounted inan undivided middle bearing 5, and the inner roller journal 3.1 of thesecond or middle roller module 3 is mounted in an undivided middlebearing 6. Both of the middle bearings 5, 6 are advantageously designedrelatively short in their axial extent, which means that the transitionregion 7 between the roller modules 2, 3 and 3, 4 are likewise designedrelatively short, so that advantageously a bulging of the cast metalstrand (slab) is minimized or greatly reduced.

The outer roller journal 2.2 of the roller module 2 and the outer rollerjournal 4.1 of the roller module 4 of the strand guide roller 1 are eachmounted in an outer bearing 8 and 9, respectively.

The second or middle roller module 3 is not mounted in the middlebearing 5, and the third roller module 4 is not mounted in the middlebearing 6. A plug connection, for example, is provided as the means ofconnection between the respective roller modules 2, 3 and 3, 4. In thisregard, as is seen best in FIG. 6, the roller modules 3 and 4 have arecess 10 on their end face that faces the first roller module 2 and thesecond roller module 3, respectively. A component 23, for example, onewith an annular design, is inserted into this recess in such a way thatit is secured against rotation. An extension 2.1.1 or 3.1.1 of therespective roller journal is machine-faced relative to the rollerjournal itself and can be connected in a positive-locking way with thecomponent 23. Further details of the positive-locking connection or plugconnection will not be discussed here, since these are not objects ofthe present invention.

As FIG. 1 also shows, each roller module 2, 3, 4 has a first and secondcentrally running flow channel 11 and 12, respectively. In this regard,the flow channel 11 of the roller module 2 can be connected to a coolantinlet 13, and the flow channel 12 of the roller module 4 can beconnected to a coolant outlet 14.

To allow complete cooling of each roller module of the strand guideroller 1, i.e., not only cooling of the core region and bearing regionbut also cooling of the region near the surface, each of the rollermodules has additional flow channels and connecting channels, which,together with the centrally running flow channels 11, 12, form an opencoolant circulation in each roller module 2, 3, 4 and, ultimately, ineach strand guide roller 1 designed in accordance with the invention.

To this end, as shown in FIG. 2, axially running flow channels 15, 16are formed in the region near the surface of the outer periphery of eachroller module 2, 3, 4 that guides and supports the metal strand. Firstconnecting channels 17 and second connecting channels 18 connect theaxially running flow channels 15, 16 with the centrally running flowchannels 11, 12 to form an open coolant circulation.

In this regard, the coolant circulation is formed in such a way that, asFIG. 3 shows, the flow channels 15, 16 are arranged in pairs in theregion near the surface, and, specifically, are preferably regularlydistributed around the periphery, where one of the flow channels of thepaired flow channels 15, 16 is connected by the connecting channel 17with the supply-side outlet 11.1 of the flow channel 11, and the otherflow channel of the paired flow channels 15, 16 is connected by theconnecting channel 18 with the discharge-side inlet 12.1 of the flowchannel 12.

As is best seen in FIG. 2, the paired flowed channels 15, 16 are eachsealed at the end, individually or together, by covers 19 and 27 in sucha way that these ensure a change in the direction of flow of the coolantin conjunction with corresponding chambers 20 formed at the end face inthe given roller module.

A special advantage of a coolant circulation of this type is that theconnecting channels 17, 18 are placed in each roller module 2, 3, 4 atthe journal end in the direction of the coolant inlet 13, and thus theperipheral surface of each roller module is free of any machiningprocess for forming connecting channels with necessarily present sealingelements. In the mounted state of the strand guide roller 1, each secondcentrally running flow channel 12 of the roller modules 2 and 3 isconnected by a coupling sleeve 21 with the respective first centrallyrunning flow channel 11 of the roller module 3 and 4. As a result, theopen coolant circulation of each roller module is brought together toform an open coolant circulation of the strand guide roller 1.

To provide better understanding of the coolant circulation within thestrand guide roller 1, the direction of flow of the coolant 22 from thecoolant inlet 13 to the coolant outlet 14 is indicated by directionalarrows.

The coolant 22 flowing into the flow channel 11 of the roller module 2flows at the end of the flow channel 11 into the connecting channel 17and enters flow channel 15 of the paired flow channels 15, 16. At theend of flow channel 15, the coolant 22 is carried into flow channel 16of the paired flow channels 15, 16 and enters the discharge-side inlet12.1 of the second centrally running flow channel 12, from which it iscarried into the first centrally running flow channel 11 of the rollermodule 3 via the coupling sleeve 21.

The further course of the flow of the coolant 22 in the roller modules 3and 4 occurs analogously to the course of the flow described for rollermodule 2, so that there is no need to provide further details here.

FIG. 2 is an enlarged detail view of section “Z” in FIG. 1 and shows therelevant design of the flow channels and connecting channels of rollermodule 2 and the direction of flow of the coolant 2. The same parts inFIGS. 1 and 2 are identified by the same reference numbers.

FIG. 3 is a cross-sectional view along line D-D in FIG. 1. It shows theregion of the plug connection between roller module 2 and roller module3 as well as the axially running flow channels 15 and 16, which arearranged in pairs in the region of roller module 3 near the surface,with the cover 27 removed. Each pair of flow channels 15, 16 comprises aflow channel 15 with coolant 22 flowing in and a flow channel 16 withcoolant 22 flowing out. The flow channels in a paired set of flowchannels 15, 16 are connected with each other by a chamber 20 placed inthe roller module. In addition, the drawing shows the second centrallyrunning flow channel 12 in the roller journal 2.1 of the roller module2.

FIG. 4 is a cross-sectional view of roller module 3 along line B-B inFIG. 1 with the paired flow channels 15 and 16 arranged near the surfaceand with the centrally arranged, first flow channel 11.

FIG. 5 is a side view of roller module 3 shown in FIG. 6. The axiallyrunning flow channels 15, 16, which are arranged in pairs in the regionof the roller module 3 that is near the surface, are tightly sealed atthe end with a preferably detachable individual or common cover 27. Thedrawing also shows the centrally running flow channel 11, 12 of theroller module 3.

The flow channel 11 is connected with the respective flow channels 15 ofthe paired flow channels 15, 16 by the connecting channels 17, which runat an acute angle, while the flow channel 12 is connected with therespective flow channels 16 of the paired flow channels 15, 16 by theconnecting channels 18, which run at an acute angle.

FIG. 6 shows a longitudinal section along line C-C in FIG. 5. The rollermodule 3 and roller journal 3.1 are shown once again in a clearlyunderstandable way. Also shown is the preferably polygonally designedextension 3.1.1 of the roller journal 3.1.

In addition to the arrangement of the flow channels and connectingchannels that has already been described in detail above, the rollermodule 3 has a recess 10, which is located on the end face that facesaway from the roller journal 3.1. The recess 10 holds an annularcomponent 23, which is secured against rotation by suitable securingmeans 24, for example, dowel pins. In this regard, the inside of theannular component 23 has a cross section that corresponds to thecross-sectional shape of the extension 2.1.1 of the roller journal 2.1,for example, a polygonal shape. On the inlet side of the central flowchannel 11, the recess 10 is followed by a mounting bore 25 for thecoupling sleeve 21 (see also FIG. 1). In this regard, the diameter ofthe mounting bore 25 is greater than the diameter of the centrallyrunning flow channel 11. In addition, the extension 3.1.1 of the rollerjournal 3.1. of the roller module 3 has a mounting bore 26 that servesthe same purpose.

FIG. 7 is another side view of the roller module 3 shown in FIG. 6. Asin the design according to FIG. 5, in the region near the surface, thepaired flow channels 15, 16 are arranged around the flow channel 11 or12 and are sealed by covers 19. A chamber 20, which is shown only inFIG. 6, joins the paired flow channels 15, 16, so that the flow of thecoolant 22 is deflected in it.

The side view also shows the polygonal design of the extension 3.1.1 aswell as the mounting bore 26 for the coupling sleeve 21 and thecentrally running flow channel 12, 11.

LIST OF REFERENCE NUMBERS

-   1 strand guide roller-   2 roller module-   2.1 inner roller journal-   2.1.1 extension-   2.2 outer roller journal-   3 roller module-   3.1 roller journal-   3.1.1 extension-   4 roller module-   4.1 outer roller journal-   5 middle bearing-   6 middle bearing-   7 transition region-   8 outer bearing-   9 outer bearing-   10 recess-   11 flow channel-   11.1 supply-side outlet-   12 flow channel-   12.1 discharge-side outlet-   13 coolant inlet-   14 coolant outlet-   15 flow channel-   15.1 discharge-side outlet-   16 flow channel-   16.1 supply-side outlet-   17 connecting channel-   18 connecting channel-   19 cover-   20 chamber-   21 coupling sleeve-   22 coolant-   23 component-   24 securing means-   25 mounting bore-   26 mounting bore-   27 closure cover

1-13. (canceled)
 14. A modular strand guide roller for a strand guideunit of a continuous casting plant, wherein the strand guide rollercomprises: at least a first and a second roller module, which aredisposed side by side in an axial direction, wherein the first rollermodule has a centrally located roller journal at an end face that facesthe second roller module; a middle bearing, which is positioned betweenthe first and second roller modules for mounting and supporting theroller journal of the first roller module; a plug connection formedbetween the second roller module and the roller journal for plugconnection of the first and second roller modules with each other; and acentral flow channel that runs axially in the roller modules forconveying a coolant, wherein the centrally located and axially runningflow channel consists of a first separate flow channel and a secondseparate flow channel; wherein flow channels are formed in the regionnear the surface of an outer periphery of each roller module that guidesand supports the metal strand; wherein first connecting channels connectrespective flow channels with the first separate flow channel, andsecond connecting channels connect further respective flow channels withthe second separate flow channel; and wherein the flow channels arearranged in pairs.
 15. The strand guide roller in accordance with claim14, wherein a chamber is formed at least at one end of each pair of flowchannels to deflect the coolant.
 16. The strand guide roller inaccordance with claim 15, wherein the flow channels and the chambers aretightly sealed from outside with detachable individual or common annularcovers.
 17. The strand guide roller in accordance with claim 14, whereinthe respective flow channels of the paired flow channels are connectedby the first connecting channels with the respective first flow channel,and the further respective flow channels of the paired flow channels areconnected by the second connecting channels with the respective secondflow channel.
 18. The strand guide roller in accordance with claim 17,wherein the first connecting channel connects a supply-side outlet ofthe first flow channel with a discharge-side inlet of the respectiveflow channel of the paired flow channels.
 19. The strand guide roller inaccordance with claim 17, wherein the second connecting channel connectsa supply-side outlet of the further respective flow channel of thepaired flow channels with a discharge-side inlet of the second flowchannel.
 20. The strand guide roller in accordance with claim 14,wherein the first flow channel of the first roller module is connectableto a coolant inlet, and the second flow channel of a respective rollermodule is connectable to a coolant outlet.
 21. The strand guide rollerin accordance with claim 14, and further comprising a coupling sleeveprovided to connect the second flow channel of the first roller modulewith the first flow channel of the second roller module.
 22. The strandguide roller in accordance with claim 1, wherein a direction of flow ofthe coolant is reversible.
 23. The strand guide roller in accordancewith claim 14, wherein the first and second separate flow channels areeach formed as sections of a common central flow channel and areseparated from each other only by a barrier.
 24. The strand guide rollerin accordance with claim 14, wherein the flow channels are formedaxially parallel, helically, or as an annular gap in a region of theroller module that is near the surface.
 25. A strand guide unit for ametal strand emerging from a mold of a continuous casting plant, whereinthe strand guide unit has at least one strand guide roller that consistsof a first roller module and a second roller module designed inaccordance with the features of claim
 14. 26. A method for operating astrand guide unit in accordance with claim 25, wherein the coolant flowsin opposite directions in adjacent strand guide rollers, adjacent rollersegments, or in an upper and lower frame of a segment.